Hypotenuse
by Cyokie Revott
Summary: If it had been his choice, Shinya would not have been present at this wedding. Alternate continuation, in a strangely minor but still important way. One-sided Guren x Shinya (on Shinya's side) and really messed up Guren x Mahiru.


**_A/N:_** _All right! This is my first Seraph of the End fic, and I have only read bits and pieces of the light novels, meaning I have EXTREMELY limited knowledge of the relationship between Guren, Shinya, and Mahiru. Not to mention I've only read volumes one through eight of the main manga, although I am in touch with several spoilers. Please forgive me if the characterization is completely wrong._

 _The story reads correctly to me, but it might not read correctly to somebody who is familiar with the dynamics of Guren, Shinya, and Mahiru. Also, this fic can take place pretty much whenever you want in an alternate continuation where Mahiru didn't turn into a demon (and it isn't really explained why this is possible in the fic pssh), but I like the pretend this takes place two years after the events of the light novels._

 _One last thing: I actually meant to write more, but at the time of posting this I'm getting ready to go away to sleep-away camp for a week, meaning I don't really have time to finish this the way I want to. This may or may not be continued._

* * *

He is overwhelmed by the scent of fragrant flowers, and on any other day it might be able to pass for some type of natural aromatherapy, but today it does not. Looking around at the elaborate decorations adorning the gorgeous garden makes a repulsively saccharine flavor override all other tastes in his mouth. The attendees, the meaningless chatter assaulting his ears from every possible angle, each small detail makes this event feel no better than a plague.

If it had been his choice—if it had been an option—Shinya would not have been present at this wedding. He glances over at the gigantic cake, formal but still beautiful, frosted white with adornments a diluted light blue. Normally, he would be wondering how to sneak a taste of the delicacy, as he is not above indulging in excessive amounts of sugar. Unfortunately, at this specific point in time, the only thing he could possibly do to such a cake is vomit on it.

Mahiru looks wonderful tonight, although Shinya will not even consider complimenting her. Her dress is elegant and classic, sleekly framing her figure and draping her with untainted white, purer than Mahiru herself could ever hope to be. The gown is flattering to her already-astounding appearance, and she _knows_ it; she's walking around with her shoulders back and chin up, as if she is a queen. A ruler of something important. Which, Shinya supposes, she is.

But Shinya won't let his eyes stray to Guren. Not unless Guren approaches _him,_ which is absolutely a rare occurrence at a gathering of this nature, so focused on Guren and Mahiru's unition. And no matter what the circumstances are, Shinya will _not_ allow himself to _take in_ how delightful Guren looks tonight. This is a rule, even if his gaze ends up sweeping over Guren for a single, brief second. It can't affect his demeanor in any way, shape or form.

The male Hiragi smiles politely whenever somebody looks his way, fidgeting idly with his fingers. Infrequently, he will be urged to speak as well, in which case he will simply give the most expected and accepted of responses. His own emotions don't have a place at the wedding of Guren Ichinose and Mahiru Hiragi. They're too personal, too worthless, and in spite of the fact that he doubts he would receive any in the first place, Shinya does not want anyone's pity.

He _should_ be celebrating, and he grinds his teeth together in frustration as he realizes he's despising himself more and more every second he isn't. Just for now, _just for now,_ can't he push away his regrets, swallow his pride, and participate in this lovely rendezvous? Can't he have his eyes settle on Mahiru without feeling a cold flash of rage? On _Guren_ without the yearning gnawing at him from the inside?

Shinya's stomach feels sickly empty, and he gets the urge to purge himself of whatever contents it has left. But he doesn't, because what would that make him? Throwing up at his best friend's wedding, all because he has no goddamn self-control anymore? Even the idea of such a thing disgusts him, and he will try his best not to entertain it, but it will not work.

Finally, _finally,_ he lets himself look up. His now-dull blue eyes meet his best friend's electrifying purple ones from across the garden, and Shinya knows in his heart it's a wrong decision, can feel it in the constricting of his chest and the tightening of his throat, but he does it anyway.

Neither of them are blinking. People must be noticing, wondering why they're just _looking_ at each other, Shinya thinks, but can't bring himself to care as Guren, still staring at him, takes Mahiru's smooth, pale, delicate hand. The black-haired man gives off an air bolder than he could ever hope to, demanding respect and holding authority, and he looks so beautiful and strong and _secure._

Shinya Hiragi wants to cry.

At this moment, he loves Guren Ichinose more than he ever has.

And it _hurts._

…

Mahiru's hand is in his, and he can't help but marvel at how much smaller and more fragile it is than his own. The warmth of the contact gives him comfort, even as he's gazing awkwardly into his best friend's eyes from the other side off this ridiculously extravagant garden. It reminds him, more than anything else, that Mahiru, irreplaceable and unapologetic, is _here._ And he's _here_ too, intertwining their fingers, thinking about how, like everything else about his bride, her hand is _perfect._

Abruptly, Guren grips her hand too tightly and bites his lip for half a millisecond.

No, that's not right.

What in _hell_ about Mahiru Hiragi is _perfect?_

He loves her. Guren knows that if he knows anything at all, and losing her would be the equivalent of losing his own soul, having it ripped from within his body. Without her, what does he have left?

Himself.

He wants to say that's enough to keep him going, that he's as intense and indestructible as he likes to think he is, but the truth is, he has never been enough for himself. His mind has been reduced to _MahiruMahiruMahiru,_ all day every day, and _this_ is how much he loves her.

But he will die before he can explain why.

Because Guren knows this sick game they're playing, this tango they make of hurting one another, and when will it _stop?_ Mahiru is beginning to successfully overthrow the influence of the demon that has been festering within her for years upon years, and Guren wants to say things will get better once she fully rids herself of the demon's impact. But is the demon really what she's fighting?

Somewhere, Guren understands Mahiru would have to destroy _herself_ in order to demolish the calamitic portion of their relationship. There has never been a time he didn't know. He has always known this, but knowing it is a curse, and he can't stand thinking about it. The demon exploits parts of you that already _exist_ ; it doesn't create new ones. And the parts of Mahiru that already exist, even alone, are…

He drops her hand as if it is a hot coal, at the same time realizing Shinya has moved on and is sitting somewhere else, sipping on something that looks like alcohol but could very well be something else. Shinya has never been much of a drinker.

Guren swallows, and his saliva moving down his throat burns like acid.

"Mahiru, can I...can I have a minute?"

He can't stay here with her for much longer. If he does, he won't survive the night.

Would it be better not to?

"Yeah...if you really need one." Mahiru looks mildly pissed, but Guren can't find it within him to give a crap what does and doesn't bother her. They're married, he can feel the ring on his finger— _God, he can feel it_ —and it doesn't matter what he does now that they've said their vows and _I do_ s, right?

Right.

He starts walking aimlessly to nowhere and nobody in particular, to something far from Mahiru, far from the potential huge mistake he's made. Why has he married her? Because he loves her?

Yes, Guren thinks, begging himself to _believe_ it. That is why he has married Mahiru Hiragi. Because he loves her more than anything else in the world, and she is the proof that there _are_ things to live for in this messed up world—

No, that's all wrong.

Guren married her because he will die without her.

…

Shinya thinks that, for him, Guren is like the sun. He is the center of the universe, but if you stare for too long…

Well.

You'll burn to death.

And that's exactly what happened to him—mentally, of course. None of the other wedding guests are able to observe Shinya as a pile of smoldering ashes lying limp on the ground. Perhaps that is his true form, above all other things. Something worn out and worthless. Something to be stepped on or swept aside.

So he had to walk away. He couldn't keep staring. He obtained a wine glass and filled it with—surprise—wine, and was sipping from it, forcing the substance past his lips and down his throat. He hates drinking, if he's being honest. He doesn't like the taste of alcohol, he doesn't like being drunk, and he doesn't like the lingering confusion the next morning, or the occasional hangover that feels like an animal pounding at him from within his skull.

Shinya is drinking tonight. It doesn't matter anymore if he likes it or not.

Maybe, if he gets drunk, he'll be able to forget, if only for a little—

His eyes widen.

That's Guren, isn't it? Walking towards him like it's no big deal. He doesn't look like he even _knows_ he's walking straight towards Shinya.

So much for _forgetting._

Shinya spitefully places his wine glass on a nearby table and runs the pristine white tablecloth between his fingers. This is the last thing he needs. Couldn't Guren have stayed with his damn bride and left his best friend _alone?_

His best friend who's been in love with him for years.

"Do you need something?"

The words slip out of his mouth before he can decide for them to do otherwise, and Shinya gives one of his award-winning smiles, gripping the tablecloth in his fist so viciously he's afraid it may rip.

He doesn't always _want_ to smile when he does so, but he has never found it _this_ difficult to fake one in the past.

Guren flinches, obviously startled and seemingly broken out of a strange trance. It only lasts for a second before he regains his cool.

How, Shinya asks himself somewhat enviously, can somebody be so _nonchalant_ about everything?

And then Guren says,

"I think I've made a mistake."


End file.
